Well, if you search on Google for the perfect or Best NSF to PST converter tool, then you will find plenty of results, but the best tool is the one that does not alter information and is safe to use. The best tool according to my experience which you give a try for free is eSoftTools NSF to PST converter. It has also won many awards for a nice performance. All elements of the mailbox can be restored in the original hierarchical structure. A free demo version is also offered to every user for trial you can try it to perform NSF file conversion free of cost.
For more info:- https://www.esofttools.com/nsf-to-pst-converter.html